lmkd: Allow killing perceptible apps when recorded stall is too high am: 5ae47a9563 am: 744462fdf0 am: 38cbc12b33 am: 915a384a57

Original change: https://android-review.googlesource.com/c/platform/system/memory/lmkd/+/1992290

Change-Id: I3820ed100c64683f6ff1c5b50405678436d02cb7

libpsi/include/psi/psi.h

@@ -22,12 +22,25 @@
 
 __BEGIN_DECLS
 
+#define PSI_PATH_MEMORY	"/proc/pressure/memory"
+
 enum psi_stall_type {
     PSI_SOME,
     PSI_FULL,
     PSI_TYPE_COUNT
 };
 
+struct psi_stats {
+    float avg10;
+    float avg60;
+    float avg300;
+    unsigned long total;
+};
+
+struct psi_data {
+    struct psi_stats mem_stats[PSI_TYPE_COUNT];
+};
+
 /*
  * Initializes psi monitor.
  * stall_type, threshold_us and window_us are monitor parameters
@@ -63,6 +76,13 @@ int unregister_psi_monitor(int epollfd, int fd);
  */
 void destroy_psi_monitor(int fd);
 
+/*
+ * Parse psi file line content. Expected file format is:
+ *    some avg10=0.00 avg60=0.00 avg300=0.00 total=0
+ *    full avg10=0.00 avg60=0.00 avg300=0.00 total=0
+ */
+int parse_psi_line(char *line, enum psi_stall_type stall_type, struct psi_stats stats[]);
+
 __END_DECLS
 
 #endif  // __ANDROID_PSI_H__

libpsi/psi.cpp

@@ -28,8 +28,6 @@
 #include <stdio.h>
 #include "psi/psi.h"
 
-#define PSI_MON_FILE_MEMORY "/proc/pressure/memory"
-
 static const char* stall_type_name[] = {
         "some",
         "full",
@@ -41,7 +39,7 @@ int init_psi_monitor(enum psi_stall_type stall_type,
     int res;
     char buf[256];
 
-    fd = TEMP_FAILURE_RETRY(open(PSI_MON_FILE_MEMORY, O_WRONLY | O_CLOEXEC));
+    fd = TEMP_FAILURE_RETRY(open(PSI_PATH_MEMORY, O_WRONLY | O_CLOEXEC));
     if (fd < 0) {
         ALOGE("No kernel psi monitor support (errno=%d)", errno);
         return -1;
@@ -61,7 +59,7 @@ int init_psi_monitor(enum psi_stall_type stall_type,
 
     if (res >= (ssize_t)sizeof(buf)) {
         ALOGE("%s line overflow for psi stall type '%s'",
-            PSI_MON_FILE_MEMORY, stall_type_name[stall_type]);
+            PSI_PATH_MEMORY, stall_type_name[stall_type]);
         errno = EINVAL;
         goto err;
     }
@@ -69,7 +67,7 @@ int init_psi_monitor(enum psi_stall_type stall_type,
     res = TEMP_FAILURE_RETRY(write(fd, buf, strlen(buf) + 1));
     if (res < 0) {
         ALOGE("%s write failed for psi stall type '%s'; errno=%d",
-            PSI_MON_FILE_MEMORY, stall_type_name[stall_type], errno);
+            PSI_PATH_MEMORY, stall_type_name[stall_type], errno);
         goto err;
     }
 
@@ -102,3 +100,17 @@ void destroy_psi_monitor(int fd) {
         close(fd);
     }
 }
+
+int parse_psi_line(char *line, enum psi_stall_type stall_type, struct psi_stats stats[]) {
+    char type_name[5];
+    struct psi_stats *stat = &stats[stall_type];
+
+    if (!line || sscanf(line, "%4s avg10=%f avg60=%f avg300=%f total=%lu",
+        type_name, &stat->avg10, &stat->avg60, &stat->avg300, &stat->total) != 5) {
+        return -1;
+    }
+    if (strcmp(type_name, stall_type_name[stall_type])) {
+        return -1;
+    }
+    return 0;
+}

lmkd.cpp

@@ -218,6 +218,7 @@ static int thrashing_limit_decay_pct;
 static int thrashing_critical_pct;
 static int swap_util_max;
 static int64_t filecache_min_kb;
+static int64_t stall_limit_critical;
 static bool use_psi_monitors = false;
 static int kpoll_fd;
 static struct psi_threshold psi_thresholds[VMPRESS_LEVEL_COUNT] = {
@@ -1915,6 +1916,37 @@ static int vmstat_parse(union vmstat *vs) {
     return 0;
 }
 
+static int psi_parse(struct reread_data *file_data, struct psi_stats stats[], bool full) {
+    char *buf;
+    char *save_ptr;
+    char *line;
+
+    if ((buf = reread_file(file_data)) == NULL) {
+        return -1;
+    }
+
+    line = strtok_r(buf, "\n", &save_ptr);
+    if (parse_psi_line(line, PSI_SOME, stats)) {
+        return -1;
+    }
+    if (full) {
+        line = strtok_r(NULL, "\n", &save_ptr);
+        if (parse_psi_line(line, PSI_FULL, stats)) {
+            return -1;
+        }
+    }
+
+    return 0;
+}
+
+static int psi_parse_mem(struct psi_data *psi_data) {
+    static struct reread_data file_data = {
+        .filename = PSI_PATH_MEMORY,
+        .fd = -1,
+    };
+    return psi_parse(&file_data, psi_data->mem_stats, true);
+}
+
 enum wakeup_reason {
     Event,
     Polling
@@ -2500,6 +2532,7 @@ static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_
 
     union meminfo mi;
     union vmstat vs;
+    struct psi_data psi_data;
     struct timespec curr_tm;
     int64_t thrashing = 0;
     bool swap_is_low = false;
@@ -2515,6 +2548,7 @@ static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_
     int64_t swap_low_threshold;
     long since_thrashing_reset_ms;
     int64_t workingset_refault_file;
+    bool critical_stall = false;
 
     if (clock_gettime(CLOCK_MONOTONIC_COARSE, &curr_tm) != 0) {
         ALOGE("Failed to get current time");
@@ -2647,6 +2681,9 @@ static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_
     /* Find out which watermark is breached if any */
     wmark = get_lowest_watermark(&mi, &watermarks);
 
+    if (!psi_parse_mem(&psi_data)) {
+        critical_stall = psi_data.mem_stats[PSI_FULL].avg10 > (float)stall_limit_critical;
+    }
     /*
      * TODO: move this logic into a separate function
      * Decide if killing a process is necessary and record the reason
@@ -2744,6 +2781,11 @@ static void mp_event_psi(int data, uint32_t events, struct polling_params *poll_
             .thrashing = (int)thrashing,
             .max_thrashing = max_thrashing,
         };
+
+        /* Allow killing perceptible apps if the system is stalled */
+        if (critical_stall) {
+            min_score_adj = 0;
+        }
         int pages_freed = find_and_kill_process(min_score_adj, &ki, &mi, &wi, &curr_tm);
         if (pages_freed > 0) {
             killing = true;
@@ -3601,6 +3643,7 @@ static void update_props() {
         thrashing_limit_pct * 2));
     swap_util_max = clamp(0, 100, GET_LMK_PROPERTY(int32, "swap_util_max", 100));
     filecache_min_kb = GET_LMK_PROPERTY(int64, "filecache_min_kb", 0);
+    stall_limit_critical = GET_LMK_PROPERTY(int64, "stall_limit_critical", 100);
 
     reaper.enable_debug(debug_process_killing);
 }